OpenJDK / jigsaw / jake / jdk
changeset 7960:223be1d3494f
6470700: Math.random() / Math.initRNG() uses "double checked locking"
Summary: Replace class Random variable with a static final holder class
Reviewed-by: alanb, mduigou, chegar
Contributed-by: Brian Burkhalter <brian.burkhalter@oracle.com>
| author | bpb |
|---|---|
| date | Thu, 22 Aug 2013 13:32:22 -0700 |
| parents | 77a32e5df365 |
| children | 4ef82445ea20 |
| files | src/share/classes/java/lang/Math.java src/share/classes/java/lang/StrictMath.java |
| diffstat | 2 files changed, 6 insertions(+), 16 deletions(-) [+] |
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--- a/src/share/classes/java/lang/Math.java Wed Aug 21 17:17:45 2013 +0200 +++ b/src/share/classes/java/lang/Math.java Thu Aug 22 13:32:22 2013 -0700 @@ -698,11 +698,8 @@ return 0; } - private static Random randomNumberGenerator; - - private static synchronized Random initRNG() { - Random rnd = randomNumberGenerator; - return (rnd == null) ? (randomNumberGenerator = new Random()) : rnd; + private static final class RandomNumberGeneratorHolder { + static final Random randomNumberGenerator = new Random(); } /** @@ -729,9 +726,7 @@ * @see Random#nextDouble() */ public static double random() { - Random rnd = randomNumberGenerator; - if (rnd == null) rnd = initRNG(); - return rnd.nextDouble(); + return RandomNumberGeneratorHolder.randomNumberGenerator.nextDouble(); } /**
--- a/src/share/classes/java/lang/StrictMath.java Wed Aug 21 17:17:45 2013 +0200 +++ b/src/share/classes/java/lang/StrictMath.java Thu Aug 22 13:32:22 2013 -0700 @@ -678,11 +678,8 @@ return Math.round(a); } - private static Random randomNumberGenerator; - - private static synchronized Random initRNG() { - Random rnd = randomNumberGenerator; - return (rnd == null) ? (randomNumberGenerator = new Random()) : rnd; + private static final class RandomNumberGeneratorHolder { + static final Random randomNumberGenerator = new Random(); } /** @@ -709,9 +706,7 @@ * @see Random#nextDouble() */ public static double random() { - Random rnd = randomNumberGenerator; - if (rnd == null) rnd = initRNG(); - return rnd.nextDouble(); + return RandomNumberGeneratorHolder.randomNumberGenerator.nextDouble(); } /**